High-speed tensor tomography: iterative reconstruction tensor tomography (IRTT) algorithm
Journal article, 2019

The recent advent of tensor tomography techniques has enabled tomographic investigations of the 3D nanostructure organization of biological and material science samples. These techniques extended the concept of conventional X-ray tomography by reconstructing not only a scalar value such as the attenuation coefficient per voxel, but also a set of parameters that capture the local anisotropy of nanostructures within every voxel of the sample. Tensor tomography data sets are intrinsically large as each pixel of a conventional X-ray projection is substituted by a scattering pattern, and projections have to be recorded at different sample angular orientations with several tilts of the rotation axis with respect to the X-ray propagation direction. Currently available reconstruction approaches for such large data sets are computationally expensive. Here, a novel, fast reconstruction algorithm, named iterative reconstruction tensor tomography (IRTT), is presented to simplify and accelerate tensor tomography reconstructions. IRTT is based on a second-rank tensor model to describe the anisotropy of the nanostructure in every voxel and on an iterative error backpropagation reconstruction algorithm to achieve high convergence speed. The feasibility and accuracy of IRTT are demonstrated by reconstructing the nanostructure anisotropy of three samples: a carbon fiber knot, a human bone trabecula specimen and a fixed mouse brain. Results and reconstruction speed were compared with those obtained by the small-angle scattering tensor tomography (SASTT) reconstruction method introduced by Liebi et al. [Nature (2015), 527, 349–352]. The principal orientation of the nanostructure within each voxel revealed a high level of agreement between the two methods. Yet, for identical data sets and computer hardware used, IRTT was shown to be more than an order of magnitude faster. IRTT was found to yield robust results, it does not require prior knowledge of the sample for initializing parameters, and can be used in cases where simple anisotropy metrics are sufficient, i.e. the tensor approximation adequately captures the level of anisotropy and the dominant orientation within a voxel. In addition, by greatly accelerating the reconstruction, IRTT is particularly suitable for handling large tomographic data sets of samples with internal structure or as a real-time analysis tool during the experiment for online feedback during data acquisition. Alternatively, the IRTT results might be used as an initial guess for models capturing a higher complexity of structural anisotropy such as spherical harmonics based SASTT in Liebi et al. (2015), improving both overall convergence speed and robustness of the reconstruction.

tensor tomography


small-angle X-ray scattering

iterative reconstruction algorithm


Zirui Gao

Swiss Federal Institute of Technology in Zürich (ETH)

Paul Scherrer Institut

Manuel Guizar-Sicairos

Paul Scherrer Institut

Viviane Lutz-Bueno

Paul Scherrer Institut

Aileen Schröter

Swiss Federal Institute of Technology in Zürich (ETH)

Marianne Liebi

Chalmers, Physics, Materials Physics

Paul Scherrer Institut

Markus Rudin

Swiss Federal Institute of Technology in Zürich (ETH)

Marios Georgiadis

New York University

Swiss Federal Institute of Technology in Zürich (ETH)

Acta Crystallographica Section A: Foundations and Advances

2053-2733 (eISSN)

Vol. 75 223-238

Subject Categories

Bioinformatics (Computational Biology)

Computer Vision and Robotics (Autonomous Systems)

Medical Image Processing



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